The present invention relates to a variable screw-driven system and more particularly, to a variable, effective screw-pitch-lead driven pressure modulation system.
Screw-driven systems for effecting a desirable pressure change in a braking system are well known devices. U.S. Pat. No. 4,653,815 which issued Mar. 31, 1987 describes one such device. The use of such a motor driven screw to effect translation of a piston that in-turn, effects a corresponding increase or decrease in fluid pressure contained within a closed braking circuit is well known.
In using such a conventional screw-driven system for effecting brake pressure modulation in wheel brake applications or releases, resulting system pressure gradients are important. A significant amount of development has concentrated on providing a motor actuator that operates to enable generation of the pressure and response times required while meeting energy limitation requirements using the now conventional screw-driven technology.
Such motor actuated screw-driven systems have proven particularly successful for use in the application and release of fluid pressure in braking systems. However, this success has resulted in the use of motor actuators that require significant amounts of energy to operate and are somewhat costly.
Electrical power consumption has become increasingly more significant as braking systems find application in electric powered vehicles in addition to the more prevalent internal combustion engine powered vehicles. Accordingly, improvements in screw-driven systems generally, and for use in vehicle braking systems in particular, would benefit from potential improvements resulting in possibly lower energy consumption requirements.